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Solid Waste Generation & Composition in Gaborone, Botswana. Potential for Resource Recovery. Jayesh Kumar Nagabooshnam

Master Thesis

ISRN number: LIU-IEI-TEK-A--12/01257—SE

Energy & Environmental Engineering

Department of Management and Engineering

Linkoping University, Sweden.

1 Solid Waste Generation & Composition in Gaborone

Abstract

An analysis of solid waste management was performed in Gaborone, Botswana to identify the

quantity of different types of solid waste that are generated annually and the possible

strategies for improved waste management. In order to achieve the objective of the project,

present waste management practice in Gaborone was analysed and waste composition study

was carried out in Gamodubu landfill, Gaborone. Waste from household, commercial,

industrial and others (defence and institutional) stratums were selected for sampling.

Different samples were taken and forwarded to sorting analysis. The waste was categorized

into 10 categories and one of the categories (plastic) is further divided into 5 Subcategories.

The output of the study results the quantity of solid waste generated in Gaborone,

composition of solid waste categories from different stratums and its flow to the landfill and

the quality of waste, annually. These findings helped in serving the importance and the need

of better waste management system in order to improvise the potential for resource recovery

under social considerations.

Keywords: Solid Waste Management, Waste Composition, Resource and Material recovery,

Gamodubu Landfill, Gaborone Waste Management, Short-term improvements

in waste management


Preface

This thesis comes under a section of the Master program in Energy and Environmental

engineering at Linkoping University. The project was carried out in Gaborone, Botswana in

Africa.

The researcher would like to thank all the officials who helped in this thesis directly or

indirectly for graciously allowing us to complete the thesis successfully. First of all, I like to

especially thank my supervisor, Assistant Professor Joakim Krook, Linkoping University,

Division of Environmental Technology and Management for the endeavour in formulating

the master thesis and for giving such a great opportunity. I would like to personally thank to

Associate Professor Mattias Lindhal, Linkoping University for helping us with research

funding and travelling arrangements and Dr. Philimon Odirile, University of Botswana for

coordinating with us in Gaborone throughout the thesis.

I am greatly indebted to the research institute SIDA (Swedish International Development

Cooperation Agency) and AFORSK for helping us financially by providing funds for the

thesis. I heartily appreciate our other researchers from E-waste Management in Botswana and

Waste Management in Botswana for contributing with me in many interview and field

activities.

I would like to convey my thanks and regards to my parents for being a great support

throughout my career and to my friends for encouraging and supporting, for the success of

this thesis.


Contents

1. INTRODUCTION............................................................................................................ 11

1.1 OBJECTIVE....................................................................................................................... 12

2. BACKGROUND .............................................................................................................. 12

2.1 GABORONE ..................................................................................................................... 12

2.2 WASTE MANAGEMENT PRACTICE IN GABORONE ........................................................ 13

2.2.1 Generation and collection of waste .......................................................................... 13

2.2.2 Transportation ......................................................................................................... 15

2.2.3 Final Disposal .......................................................................................................... 16

2.3 GAMODUBU REGIONAL LANDFILL ................................................................................ 17

3. THEORETICAL FRAMEWORK ................................................................................... 18

3.1 SOLID WASTE AND ITS TYPES ......................................................................................... 18

3.2 WASTE HIERARCHY MANAGEMENT ............................................................................. 19

3.2.1 Source Reduction ..................................................................................................... 19

3.2.2 Reuse ........................................................................................................................ 20

3.2.3 Recycling ................................................................................................................. 20

3.2.4 Resource Recovery ................................................................................................... 21

3.3 COMPOSITION OF SOLID WASTE MATERIALS ................................................................. 23

3.3.1 Sampling techniques used for Composition of waste .............................................. 23

3.3.2 Sampling Errors ...................................................................................................... 26

4. METHOD .......................................................................................................................... 27

4.1 DATA COLLECTION ........................................................................................................ 27

4.2 SOLID WASTE COMPOSITION STUDY AT GAMODUBU LANDFILL .................................. 28

4.2.1 Procedure for Analysing the Solid Waste Composition .......................................... 28

4.2.2 Sample size .............................................................................................................. 29

4.2.3 Tools and Equipment’s used for Sorting ................................................................. 29

4.2.4 Sorting Procedure .................................................................................................... 29

4.3 ASSESSING THE ANNUAL GENERATION RATE .............................................................. 31

4.4 CRITERIA FOR THE IMPROVEMENT OF BETTER WASTE MANAGEMENT SYSTEM .......... 31

5. RESULTS ........................................................................................................................... 32

5.1 ANNUAL GENERATION OF SOLID WASTE IN GABORONE ............................................... 32

5.2 ANNUAL COMPOSITION OF SOLID WASTE FROM DIFFERENT STRATUMS ....................... 32

5.3 AVERAGE COMPOSITION OF THE SOLID WASTE RECEIVED AT THE GAMODUBU

LANDFILL .............................................................................................................................. 33

5.4 TOTAL ANNUAL FLOW OF DIFFERENT WASTE CATEGORIES AND ITS QUALITY .......... 34

5.4.1 Total Annual flow of different plastic waste categories........................................... 35

6. DISCUSSION ................................................................................................................... 36


6.1 STRATEGIES FOR IMPROVED WASTE MANAGEMENT IN GABORONE ............................ 36

6.1.1 A need for introducing source separation systems .................................................. 37

6.1.2 Improved collection system ..................................................................................... 38

6.1.3 Social Considerations .............................................................................................. 40

7. CONCLUSION ................................................................................................................. 41

8. REFERENCES ................................................................................................................... 42

9. APPENDIX ........................................................................................................................ 47


List of Figures

Figure 1 Map of Botswana ...................................................................................................................................... 12

Figure 2 Waste collection bin at the University of Botswana .......................................................................... 14

Figure 3 Current waste collection practice in Gaborone ................................................................................. 15

Figure 4 (left) Disposing Waste in Gamodubu Landfill .................................................................................... 16

Figure 5 (Right) Incinerator for Medical Waste in Gamodubu Landfill ....................................................... 16

Figure 6 Gamodubu Regional Landfill ................................................................................................................. 17

Figure 7 Waste Hierarchy Management .............................................................................................................. 19

Figure 8 Plastic Bins Used for Sorting ................................................................................................................. 30

Figure 9 Diagrammatic Representation of Waste Categories ......................................................................... 31

Figure 10 Annual generation of solid waste (in tonnes) for different stratums of Gaborone. The

presented amounts only account for the waste delivered to the Gamodubu landfill. ................................ 32

Figure 11 Composition (in weight- %) of the annually generated waste for 4 different stratums in

Gaborone .................................................................................................................................................................... 33

Figure 12 Average composition (in weight- %) of the total sample size analysed at the Gamodubu

landfill ......................................................................................................................................................................... 34

Figure 13 Total Annual Flow of Different Waste categories to Landfill ....................................................... 35

Figure 14 Composition (in weight- %) of the annually generated plastic waste in Gaborone................. 36

Figure 15 Schematic illustration of an improved waste management system in Gaborone ...................... 39

List of Tables

Table 1 Waste Type and its Cost for Disposal in Landfill ............................................................................... 17

Table 2 Waste Type and its Code........................................................................................................................... 18

Table 3 Sampling techniques for waste composition ........................................................................................ 24

Table 4 Sampling errors to be considered for waste composition ................................................................. 26

Table 5 Tools Used for Sorting .............................................................................................................................. 29

Table 6 Average Composition of different waste categories from the sample size (2400kg) ................... 34

Table 7 Potential for Resource Recovery ............................................................................................................ 37


List of Abbreviations

ASTM American Society for Testing and Materials

BMW Biodegradable Municipal Waste

BTV Botswana Television

BWMS Botswana Waste Management Strategy

CIA Central Intelligence Agency

CIWMB California Integrated Waste Management Board

CSO Central Statistics Office

DOC Degradable Organic Carbon

EIONET European Topic Centre on Sustainable Consumption and Production

EPA Environmental Protection Agency

EU European Union

E-waste Electronic Waste

GHG Greenhouse Gas

GWM Global Waste Management

HDPE High Density Polyethylene

HHW Household Hazardous Waste

IEA International Energy Agency

LFG Landfill Gas

LLDPE Linear Low Density Polyethylene

LPDE Low Density Polyethylene

MBT Mechanical Biological Treatment

MSW Municipal Solid Waste

MSWL Municipal Solid Waste Landfill

NGO Non-governmental Organization

OCED Organisation for Economic Co-operation and Development

PET Poly Ethylene Terephthalate


PP Poly Propylene

PS Poly Styrene

PVC Polyvinyl Chloride

RCRA Resource conservation and Recovery Act

SAEFL Swiss Agency for Environment, Forests and Landscape

SWA Solid Waste Analysis Tool

USEPA United States Environmental Protection Agency

WHO World Health Organization


1. Introduction

Waste is a material or substance which is no longer to be used and meant to be discarded by

the user (EIONET, 2011). According to the Basel Convention, “wastes are substances or

objects which are disposed of or intended to be disposed of or required to be disposed of by

the provisions of national laws” (UNEP/GRID-Arendal, 2011).

From a global perspective, the generation of solid waste is mainly driven by population

growth, technology improvements and economic development. According to the European

commission, the waste generated by the European Union (EU) is around 3 billion tonnes of

waste per year, where 90 million tonnes of them are hazardous waste. This means that about

6 tonnes of solid waste are generated by each individual per year (Eurostat, 2011).

Furthermore, the Organisation for Economic Cooperation and Development (OECD) reports

that the quantity of waste generated in the period 1990 to 1995 within the European region

has increased by 10%, where 67% of the waste was landfilled. The OECD expects that by

2020 the generation of waste has increased by 45%. Waste Prevention, Recycling and Reuse,

Improving Final disposal and Monitoring are the three main waste management strategies

within the European Union (European Commision, 2011).

The Global Waste Management (GWM) Market Report (2007) show that the MSW generated

in the year 2006 was close to 2 billion tonnes with an annual increase of 7% since 2003. It

has been noted that the generation of MSW from 2007 to 2011 has been increased by 8% per

year and nearly 37.3% in a 5 year period globally. According to WHO, the low income

countries generate approximately 0.5 kg to 3 kg of total health care waste per year by an

individual. Now days, E-waste is considered as one of the most rapidly growing types of

waste with a ratio of average 1% in solid waste and reached 2% in 2010 and to be expected to

increase more in the future (Assessment of Current Waste Management System, 2009). The

per capita solid waste generation in developed countries like Canada, Switzerland, France,

United Kingdom and USA varies between 0.9 – 2.7kg per day and in the developing

countries like India, Sri Lanka and Thailand generates 0.3-0.65kg, 0.4-0.85kg and 0.5-1kg

per day (I. Korner, 2003-2006). From the total quantity of waste generated in Canada, nearly

50% is municipal solid waste. A report from the US Environmental Protection Agency

(USEPA) show that 56.9% of total waste generated in the USA is disposed of in landfills,

27% is material recycled and 16.1% is incinerated (Kuniyal, 2010).

The current handling of solid waste has a wide range of environmental implications such as

generation of methane emissions from landfills contributing to global warming, littering and

various types of pollution caused by leaching from landfills or emissions from waste

treatment facilities. Paper and plastic materials are often major components of solid waste

(Akinbode, 2010). They contain substances which are hazardous to health which may cause

skin disease, respiratory problems, carcinogenic, neurological disease, low birth weight,

chemical poisoning through inhalation. The main factors for the environmental impact of

solid waste are absence of source separation programmes, lack of technical expertise and

institutional arrangements, improper collection, segregation, transportation and disposal

methods, the person's attitude towards waste management, lack of awareness, insufficient

funds, and community involvement.


Developed regions like Europe and USA have standardised waste management methods for

different kind of waste and defined policies and legislation especially knowledge on waste

and its impacts. The amount of waste generated per capita for both developed and developing

countries may sometimes be more or less the same but the main difference is related to the

waste management strategy and practice. In developing countries like India and Thailand,

virtually all of the generated waste is landfilled. This difference in waste handling depends on

a lack of knowledge on waste and its impacts on environment and human health, improper

collection system for waste, lack of policies and measures for waste management,

unavailability of recycling options and lack of infrastructure.

Likewise other developing countries all over the world, Botswana is also facing the serious

issue of increasing solid waste generation and the main disposal route is landfilling. Apart

from that natural resources are wasted, such a practice results in various environmental

implications, ranging from local pollution concerns and land management issues to global

impacts in terms of several hazardous emissions from the landfill.

1.1 Objective

The overall objective of this thesis is to contribute with knowledge regarding the generation

and composition of solid waste in Gaborone, Botswana. This is in order to provide a

foundation for developing improved waste handling strategies, taking the present technical,

economic and organisational conditions in the country into account.

This objective is divided into the following two research questions:

How much of different types of solid waste are annually generated in Gaborone?

What are the possible strategies for improved waste management in Gaborone?

2. Background

2.1 Gaborone

Gaborone is the capital city for Botswana which is located in the south Eastern edge of the

country on the Notwane river between Kgale and Oodi hills (Njeru, 2006), figure 1 (Zambezi,

2011).

Figure 1 Map of Botswana


Botswana is situated in southern Africa which is officially called as Republic of Botswana

with the population approximately 2.1 million (year 2010) Batswana (citizens of Botswana).

Compared to other countries in the African continent Botswana has the highest grade of

economy.

Mining industries play the vital role in the economic prospective (Nocera, 2008). Initially

Botswana was one of the poorest countries in Africa with a GDP per capita of about US$70

(The World Bank, 2010), but it has since then been one of the fastest developing countries in

the region with a present GDP per capita of US$6,200 (U.S. Department of State, 2011). The

poverty also has been reduced from 50% to 30% from the time of independence (The World

Bank, 2010). Botswana is one of the world’s largest manufacturers of diamonds. Next to the

mining industry, tourism plays a vital role in the economy of Botswana.

Likewise many other countries, the capital Gaborone has all the modern facilities that could

be expected in a large-sized city, e.g. International and high-standard hotels, casinos, shops,

restaurants, hospitals, banking sector, industries, educational institution, and National

Museums. University of Botswana, one of the top educational institutions in the country is

also located in the capital (Gaborone, 1997). The city is known as governmental capital or

Economic capital, because it holds the headquarters for several companies as like mentioned

above (Njeru, 2006).

2.2 Waste Management Practice in Gaborone

The waste management issues and problems are managed by the Botswana Waste

Management Strategy which was founded in the year 1998. The aims of this strategy are to

decrease the waste generation in industry, waste minimisation in households and commercial

sectors, increase recycling and reuse and propose well-defined collection, transportation and

disposal facilities for waste (Ednah & Luo, 2010). Landfill dumping and littering are the

grievous problems to the environment, which Botswana is facing. Nearly 10,000 tons of

waste is generated in Botswana per day, according to the Central Statistics Office (CSO,

1998). Botswana local governmental bodies consider recycling services, household formation

of trends, and urban consolidation are the main factors in the generation of waste.

2.2.1 Generation and collection of waste

The solid waste generated in Gaborone can be classified into five categories. General waste,

garden waste, soil, clinical waste and construction waste. General waste, garden waste and

soil are considered as domestic waste generated by the individuals in day to day processes.

The generation of general waste and garden waste in commercial sectors and industries is

however quite high when compared with the households. The general waste can be primarily

classified into two sub categories, organic and Inorganic. The organic waste consists of food

waste, garden waste, papers and cardboards, wood and other organic materials. The inorganic

waste consists of bottles, cans, plastic, glass, electronic waste, metals and other kinds of

waste.

The individuals living in the city of Gaborone use polyethylene plastic bags for the collection

of waste generated by them in the household. The peoples living in apartments and multi


housing and institutions have a garbage container outside their buildings where the collected

waste can be dropped into containers, Figure 2.

Figure 2 Waste collection bin at the University of Botswana

The waste is generally not separated but the different types of wastes are mixed up by the

individual and then thrown into the bin. The waste generated from household is collected by

the city council once or twice per week, and the collected waste is transported to the landfill

for disposal without any pre-treatment, as Gaborone does not provide any existing recycling

or treatment units, Figure 3.

The waste generated from private organizations, commercial sectors and industrial sectors are

generally collected by non-governmental companies like Skip Hire. Collect-A-Can is a

private organisation that collects metal cans from commercial, industrial and other

institutions such as the military defence. Scavengers working at the landfill also collect cans

which are sold to the company. Scrapcor Ltd is another company in Gaborone which collects

metal scrap from large institutions, i.e. Botswana Defence force but also from households and

individuals (National Conservation Stratergy Agency, 1998). The amount of waste cans

(metals) generated in Botswana per year is around 6500 tons of which the main part is

beverage cans (Ednah & Luo, 2010). Dumatau Trading is a waste paper company which

collects paper and Simply Recycle is a private company, collecting plastic waste and

processing it into new raw material. NGO’s like Somarelang Tikologo, Kalahari

Conservation Society and Environmental Heritage Foundation are the main partners working

on waste management and minimisation (National Conservation Stratergy Agency, 1998).

Companies like Shell and Environmental system has planned to collect the used waste oil

back. So the provision of waste oil tank is placed in the collection of waste oil in all sites

where oil is used (Ednah & Luo, 2010). Despite several waste collection companies in

Gaborone, most of the waste that is recovered is collected by scavengers working at the

landfill. The recovered materials are exported to South Africa and Zimbabwe for recycling

and manufacturing of new products.

The E-Waste generated in the Gaborone is not collected by the city council, but it is the

responsibility of the users to transport and dispose the E-Waste in the landfill. Botswana

Television (BTV) established a “Computer Refurbishment Project (CRP)” in 2008, which

restore, recover, and rehabilitate used computers from governmental organizations,


households and private companies which has minor problems. Such repaired computers are

often distributed for use in domestic schools or else transported to other countries for

recovery such as South Africa and Zimbabwe (for more detailed information see (Shashidhar

Suresh, 2011)). As like E-Waste, it is the duty for the commercial sectors like shopping

malls, hotels and shops to transport their waste to the landfill by themselves. Construction

waste such as concrete, brick and sand are transported to the landfill where it is used as a

covering layer.

Figure 3 Current waste collection practice in Gaborone

2.2.2 Transportation

The collected solid waste in Gaborone is transported to the Gamodubu landfill which is

located 35 km outside the city. They use old vehicles for transporting the waste from the city

to the landfill. Due to the long distance and lack of vehicles the waste generated in the city is

not collected periodically which results in storage of waste for a long period. Recovery

companies should travel to the landfill for recovering materials and products for recycling

and because of the distance they plan to recover materials as much as possible, so vehicles

which have the capacity to carry more quantity is chosen. As the size of the vehicle increases,


fuel consumption also increases in parallel and also GHG are emitted from the vehicles as it

is old, which has impacts on the environment.

2.2.3 Final Disposal

Figure 4 (left) Disposing Waste in Gamodubu Landfill

Figure 5 (right) Incinerator for Medical Waste in Gamodubu Landfill

Most of the generated solid waste is meant to be disposed in the landfill which is considered

as a traditional approach (Ednah & Luo, 2010). A study shows that only 40% of the generated

waste is collected and disposed properly (Segosebe & Vanderpost, 1991). Because of

unconventional waste disposal, untemper disposal of waste and massive quantity of waste

generation, the quality of the local environment in the city is extremely affected (Kgathi &

Bolaane, 2001).

The generated and collected solid waste is disposed in the Gamodubu landfill of Gaborone

without any treatment and recycling activities, Figure 4. The waste is dumped up to 5m(1)

high from the ground level and covered with soil or construction waste. Recovery activities

take place in the landfill by scavengers. The recyclable materials recovered from the landfill

and other sources are transported to South Africa and Zimbabwe for the recycling process.

The bottles broken while processing are sent to South Africa for recycling. The recyclable

waste scavenged from the Gaborone landfill by individuals only was around 50 tonnes per

year in 2010 (Ednah & Luo, 2010).

The waste generated from medical facilities are packed and protected properly accordingly to

its process. Waste like syringe, equipment with sharp edges are carefully packed in a

specially designed package and other waste like cotton, cloth, bandage and more are packed

separately and sent to the landfill. The received hospital waste is incinerated in the

Gamodubu landfill in a preserved environment and condition, Figure 5.

1 metre


2.3 Gamodubu Regional landfill

The landfill is located in near the Gamodubu village for about 30km from Molepolole and

35km(2)

from Gaborone with an area of 30 hectares (Botswana Government, 2011).

Figure 6 Gamodubu Regional Landfill

The landfill, Figure 6 has 5 cells, each of them being 1.5m in depth. The cells consist of

drainage pipes which connect to the leachate pond. It is approximated that the landfill can

execute for 20 more years. The old landfill which is called Gaborone landfill was closed as it

was almost filled and presently the generated waste in the Gaborone city is disposed in this

new landfill. Waste from Gaborone and in and around districts like Tlokweng, Mogoditshane,

Molepolole is dumped in the Gamodubu landfill (Botswana Government, 2011). Gamodubu

landfill construction was started in August 2007 and was completed in January 2009. The

project was handled by a China Jiangsu International Botswana and the cost of the project

was P( 3 )

67 million including the cost for the final closure of the Gaborone landfill

(Mokgoabone, 2008). The landfill has tariffs plan for the waste coming to the landfill, Table

1 (Gamodubu Background, 2011).

Table 1 Waste Type and its Cost for Disposal in Landfill

Type of Waste Cost

Health care waste P30.00/kg

Pharmaceutical waste P30.00/kg

Food animal products (poultry waste, sawdust and yeast) P1.00/kg

Abattoir sludge P5.00/kg

Soil material (to be used as cover material) Free

Domestic waste (For Individual) Free

Domestic waste (>1000 kg/1 ton) P40.00/ton

Commercial/Industrial waste P40.00/ton

Confidential documents P40.00/ton

Garden waste P60.00/ton

Scrap metal P60.00/ton

Used tires P50.00/ton

Condemned foodstuffs P20.00/ton

2 Kilometre 3 Pula – Botswana Currency


At the end of each month the waste carrying services is billed and the bills should be paid in

Mogoditshane and Molepolole revenue offices. The paid bill should be shown at the security

in the landfill to confirm that no pending bills for the respective services. Then the waste

carrying vehicle should stop at the security gate where the vehicle number and company

details are registered. After that the vehicle is weighed in the weighing bridge and its type of

waste is registered in the computer. Table 2 (Gamodubu landfill Daily waste report) shows

the types of codes used for different types of waste.

Table 2 Waste Type and its Code

Waste Type Waste Code

Domestic waste A

Garden waste B

Medical waste C

Tyres D

Scrap metal E

Soil materials F

Condemned food stuffs J

Recyclable paper K

Electrical and Electronic waste N

Recyclable Tyres Q

Recyclable metals R

Food animal waste W

Based on the type of waste codes the vehicle is directed to the respective spots and the waste

is unloaded. The unloaded vehicle is weighed again while returning back from the landfill on

the weigh bridge to calculate the weight of the waste (Gamodubu Background, 2011).

(Weight of waste = Total vehicle weight with waste – Vehicle weight without waste)

3. Theoretical Framework

3.1 Solid Waste and its types

Solid waste is often categorized into municipal solid waste and non-municipal solid waste.

The non-municipal waste comprises of construction waste, wastewater treatment sludge,

mining waste and other industrial solid waste. The contribution of municipal waste will be

around 99% in a sample waste and the remaining will be the non-municipal waste

(ucopenaccess, 2011). According to U.S Environmental Protection Agency, 2001 the

municipal solid waste is categorized into several forms, mainly durable goods and non-

durable goods. Durable goods consist of tyres, household appliances, electric and electronic

equipment and batteries which last longer than 3 years. Non-durable goods like papers,

clothing, wood pallets and cardboards have a lifetime less than 3 years (Pollution Issues,

2011).


3.2 Waste Hierarchy Management

The management of solid waste is one of the challenging tasks in the present fast growing

world. In order to maintain a sustainable environment it is important to reduce the amount of

waste generated through recycling or reuse of discarded materials and products. According to

the waste hierarchy, the most preferred option for solid waste is source reduction followed by

re-use of whole products, recycling of materials, resource recovery in means of material and

energy, incineration and finally least preference for landfilling, Figure 7 (Waste Hierarchy

Management, 2011).

Figure 7 Waste Hierarchy Management

3.2.1 Source Reduction

Source reduction is the most preferred waste management Strategy in the hierarchy because it

eradicates the necessity of handling, transportation and disposal of waste. Change in design,

production, packaging, purchase and use of products or materials to reduce the toxicity and

amount of waste generated at the source is referred as Source reduction (USEPA, 2007).

Source reduction is therefore often argued to be the most environmentally sound management

for minimising MSW (Power Score Card, 2000). Any activity which helps in reducing waste,

toxicity, and focusing on reuse and recycling at the source is termed as source reduction. An

individual thinks, consuming fewer products and getting rid of less waste is considered as

source reduction (Sally, 2004). A manufacturer should ensure that the product should last a

long useful life thus produce environmentally sound products by cleaner production

technology. Source reduction or waste minimization and prevention strategy should be

applied in the life cycle analysis of a product from cradle to grave, so that waste generated in

each phase of the product can be identified and minimized at the earlier stages (Kulkarni,

2008). Use of reusable products, buying products with less packaging, using rags instead of

paper towels, electronic newspapers from online for reading news, electronic documents

instead of papers for payment activities, use recycling products like aluminium cans and

glass, purchase products that are non-hazardous, purchase in bulk, buy more durable


products, minimize the use of product are some of the strategies for source reduction (Source

reduction and Reuse, 2011). Source reduction serves in conserving natural resources by

producing and designing efficient product and also minimizes the quantity of waste as equal

to the waste recycled or incinerated or landfilled (USEPA, 2007).

3.2.2 Reuse

The material or product which can be used more than once for the same or different activities

without any upgrading is defined as reuse (Kulkarni, 2008). Reuse is also an option for

source reduction. The main application of reuse is to extend the life of the product or

material. Use of durable coffee mugs, towels, refilling bottles, reusing cardboard boxes,

donating old computers to schools and NGO’s, second hand furniture’s are some of the

examples for reuse. Compared to recycling, reuse is preferred most as it does not undergo any

upgrading and therefore no material and energy is used and at the same time reduces the cost

and the need for disposal (Kulkarni, 2008). The demerits in reuse are cleaning, transportation

and time consumption for sorting.

3.2.3 Recycling

Recycling is an activity of collecting, sorting and processing of used or discarded materials

into useful products to its original form or for other purposes. It is considered as one of the

effective solution for saving landfill from producing greenhouse gas. The materials from the

municipal waste can be recovered and served in the manufacturing process for producing new

products and material recovery. The foremost aim of recycling treatment method is

converting waste into valuable materials. Materials like paper, plastic, metals and glasses are

some of the recyclable materials used for recycling and manufacturing new products (I.

Korner, 2003-2006).

Papers in landfill consume more space and take approximately 5 to 15 years to break down

and decompose (Hanson, 2011). Roughly 3000KWh to 4000KWh electricity can be saved for

every 1000kg of paper used for recycling (Waste Online, 2006). According to an

Environmental report, recycling 1000kgs of mixed paper conserves energy which is equal to

185 gallons of gasoline and also saves 7000 gallons of water and nearly 3 cubic yards of

landfill space (Complete Recycling, 2011). The waste papers can be cascaded to produce new

paper based products like tissue paper, notebooks, stamps, paper bags and more. Nearly 28%

to 70% of minimum energy is consumed in producing paper products from recycled paper

when compared to virgin material (Waste Online, 2006). Recycling 1000kgs of paper saves

up to 17 trees approximately (Green StudentU, 2011). According to the statistics and facts

from the United States Environmental Protection Agency, 2011 the pollution of water and air

is reduced by 35% and 74% when paper is recycled than producing new paper (Benefits of

Recycling, 2011).

Recycling of plastic is a more efficient method for material and energy recovery than

incinerating and disposing. When plastic is incinerated it highly emits greenhouse gases

which are one of the main causes for environmental impact. It consumes twice the energy for

incinerating the plastic rather than recycling (Recycling Revolution, 2011). When 1000kgs of

plastic is recycled it saves up to 7.4 cubic yards of landfill space (Benefits of Recycling,


2011). Nearly 10% of energy will be consumed to produce new plastic products from

recycled plastic when compared to virgin materials (Bloch, 2010).

Metal recycling generally leads to material recovery, energy recovery, and minimization of

virgin metals consumption and reduced greenhouse gas emission. According to EU report,

utilizing recycled raw materials for the production of new materials decreases around 200

million tonnes of CO2(4)

emission per year (BMRA, 2010). Recycling aluminium conserves

nearly 95% of energy used for producing new aluminium products from virgin aluminium

(Buxmann, et al.). So, 5% of total energy is used for producing aluminium products with only

5% of CO2 emission (BMRA, 2010). A single aluminium can when recycled conserves

enough energy which can enable to run a television for 3 hours. When 1kg of aluminium is

recycled it merely saves 6kg of bauxite, 4kg of chemical products and 14KWh of electricity

(Benefits of Recycling, 2010).

Glass is the product which does not lose its purity and quality even after recycling for several

times (West , 2011). When 1000kg of recycled glass is used for producing new glass

products, nearly 1200kgs of raw materials are conserved (Waste Online, 2006). According to

the Glass Packing Institute, recycled glass consumes only two third of energy for producing

glass products. Glass recycling facilitates the environment by reducing the amount of CO2

(GHG) exposing to the atmosphere by 315kg per ton, considering transport and processing

emission (Bloch, 2010).

Recycling serves in conserving resources for future, consumes less energy than producing

products from virgin materials, uses and saves valuable metals from dumping, develop

sustainability and reduces landfilling.

3.2.4 Resource Recovery

3.2.4.1 Composting

Composting is a natural way of recycling (Benefits of Recycling, 2010). It is a biological

process which decomposes the organic matters into various micro-organisms under aerobic

conditions (ucopenaccess, 2011). In this process prominent fraction of degradable organic

carbon (DOC) from the waste is changed into carbon dioxide (CO2). Emission of CH4(5)

is

oxidised in this process to a large extent. The result in this process which is called as Humus

is generated from the organic matter act as a main component for the fertile soil. Composting

is an option to retain the nutrients from the waste and deliver back to other organisms in the

natural system (ucopenaccess, 2011). Materials like garden waste, lawn clippings, leaves,

weeds, hay, straw, wood products, food waste and manure are used for composting

(Envirotech Ltd). Soil enrichment, remediate contaminated soil, pollution prevention

(USEPA, 2011), reduction in GHG, regeneration of poor soils (Environmentalist Everyday,

2011), minimize soil erosion, better soil porosity, less consumption of fertilizers and

pesticides, high nutrients to soil are the environmental benefits of composting. Composting

also has environmental impacts by polluting surface, ground water, soil and air due to the

4 Carbon dioxide 5 Methane


residuals in the process. High investment costs, need of large covered area, need of sorts

waste are the other disadvantages of composting.

3.2.4.2 Anaerobic Digestion

Anaerobic digestion is a natural biological decomposition process of organic matters by

maintaining the heat, pH value and moisture content in the absence of oxygen (Alves, et al.,

2006). As a result, biogas is generated from the process. The biogas consists of 60% of CH4

and remaining 40% of CO2 (Friends of Earth, 2007) and it is separated. Methane is extracted

and is used as fuel for vehicles or may be used as heat and electricity (Alves, et al., 2006) and

the left out CO2 is exposed to the atmosphere. After the extraction of biogas the remaining

residue i.e. digestate is used as fertility for the agricultural lands (Friends of Earth, 2007). On

an average 100 to 200 cubic meters of bio gas is produced from 1000kg of organic waste

(Ann.C, 2011) and 1 cubic meter of bio gas serves in generating 1.7KWh(6)

electricity and

7.7MJ(7)

of heat. Organic waste like sewage sludge, organic farm waste, municipal solid

waste, green waste, industrial and commercial waste are used in anaerobic digestion

processes (Monnet, 2003).

Recently mechanical-biological treatment is getting familiar in most of the countries

especially in Europe. In this MBT the solid waste is sorted mechanically accordingly to the

disposal option (recycling, incineration, composting, anaerobic digestion and landfill) and

then the waste which is to be digested using anaerobic digestion is fed to the biological

treatment and processed (Alves, et al., 2006). The process helps in minimizing GHG and the

energy produced from the process decreases the demand of fossil fuels and the resulted

digestate also helps in minimizing the synthetic fuels used for fertilizer production. The

anaerobic digestion has some potential impacts on the environment as the development

increases and consumes a high operational cost and investment for processing (Monnet,

2003).

3.2.5 Incineration

Waste Incineration is an approach in the waste management hierarchy, which is majorly used

in European and American countries, instead of disposing the waste in the landfill. Burning

of solid waste materials at a very high temperature (ucopenaccess, 2011), is known as

incineration. Electricity and heating are the main products of waste incineration. The heat

produced in burning the trash is used for generating electricity power and used for heating in

cold countries, which is technically pronounced as waste to energy. The residue after burning

the waste is used to extract some of the non-combustible materials like glass, metals (North

Yorkshire County Council, 2010) etc. and rest of the fly ash is used as a mixture for

engineering purposes (Friends of Earth, 2002) and at worst case it is dumped in the landfill.

Comparatively the fly ash consumes less space in the landfill subjected to solid waste. The

main purpose of incineration minimises the volume of combustible by 80% to 90% (Decision

Makers’ Guide to Municipal Solid Waste Incineration, 1999). The advantages of incineration

are it majorly minimizes the volume of waste being dumped in the landfill, produce energy

with the heat produced during combustion (Statistics Canada, 2010). On an average of

6 Kilowatt hour 7 Mega joule


525KWh electricity can be generated by incinerating 1000kg of combustible waste from

MSW (Combs, 2008). Waste like paper, textiles, garden, wood, plastics comes under

combustible materials. The disadvantages of incineration are air pollution, emission of

chemicals which produce acid rain and ground level ozone, metals (Zinc, Cadmium, Mercury

and Nickel) changes to ash when incinerated which lead to loss of metals (Statistics Canada,

2010).

3.2.6 Landfill

Landfill is a place where the generated wastes are dumped beneath the soil in an isolated

manner. It is one of the more often used methods for the disposal of waste. Around 62% of

municipal wastes are dumped in the landfill (Infoplease, 2000). Due to the landfill disposal

facility many of the developing countries like Botswana, India are dumping their solid waste

instead of recycling or reusing or may be fed to other disposal methods. The main reason for

the closure of landfills at present in many countries is due to the fulfilment of waste in the

landfill and then only comes the life span of the landfill. Plastic and paper waste contributes

major part in land acquisition in the landfill as it is generated numerously and disposed at a

great extent. The environmental impacts due to landfill dumping are Ground water

contamination, Air pollution, Leachate, Emission of CH4 gas, consumption of large volume

of land leads to land scarcity and soil acidification, deposition of metals and scare elements

which intern leads to resource scarcity and waste of energy for extraction of resources. It also

affects the human life by respiratory disease, cancer, birth defects and skin disease (Enviros

Consulting; University of Birmingham;).

3.3 Composition of Solid waste materials

Solid waste composition studies are mainly used for constructing a well-defined waste

management for several reasons which admits potential for material recovery, to find out the

origin of component generation, thermal, to approximate its chemical and physical properties.

Seasonal change and geographic aspect are the factors which influence waste composition

study (Debra & McCauley, 1996). Waste is sorted based on the waste categories for the

composition. Initially a sample wastes is selected and it will be separated into different

categories based on its source of origin, physical and chemical properties and its

characterization. Then the separated waste is further broken down specifically into different

types and the materials or substance in the waste is segregated according to it. Commonly,

the waste is broken down into paper, wood, textile, food, rubber, leather, plastics, garden

waste, metals, glass, e-waste, soil waste and more. The selection for specific type differs

based upon the selector. Now the segregated waste is collected separately and it is weighed.

Comparing the weight of the segregated waste with the sample selected and its composition is

calculated.

3.3.1 Sampling techniques used for the composition of waste

Practically thinking it is not possible to calculate or find the waste composition for the whole

waste generated in Gaborone, so a sampling method should be used to calculate the waste

composition in a sample and it is compared and related with the total waste generation

quantity. There are several waste sampling methods used earlier for finding the composition

of waste generated. Sweden and many others countries in Europe also use different sampling


methods for waste composition. The below describes the methods, Table 3 does not come

under international standards and there are no methods assigned for international standards

(Dahlen & Lagerkvist, 2007).

Table 3 Sampling techniques for waste composition

Reference

Method

Sample

size

Stratification

Sampling

method

Sorting

process

ASTM (2003) Standard test

method for

determination of

the composition

of unprocessed

MSW

Mass Selection of

vehicles

arriving to a

specific waste

treatment site

Coning

&quartering of

waste from a

cross-section of

discharged load

Manual

CIWMB

(1999)

Uniform waste

disposal

characterization

method

Mass Geographic,

climatic,

demographic,

economic,

single/multi-

family, self-

haul

Single family:

from a 16 cell-

grid over a

discharged load.

Multifamily:

Cross-section

from dumpster

Manual

RIVM

(Cornelissen

and Otte,

1995)

Physical

investigation of

the composition

of household

waste in

Netherlands

Number of

households

11 socio-

economic

categories,

collection

variables

No sampling

method

Manual

Environmental

Agency of

England and

Wales

Assessing the

composition of

MSW

Number of

households

Community

type,

collection

variables

No sampling

method

Manual

European

Commission

(2004)

SWA-tool,

Methodology for

the analysis of

solid waste

Volume of

waste bins

Residential

structure,

collection

variables and

others

No sampling

method

Combined

manual &

screening

University of

Central

Florida

(Reinhart and

McCauley-

Bell, 1996)

Methodology for

conducting

composition

study for

discarded solid

waste

Mass Selection of

vehicles

arriving to a

specific waste

treatment site

Coning

&quartering of

waste from a

cross-section of

discharged load

Manual

Nordtest

(1995)

Solid waste,

municipal:

sampling and

characterization

Number of

households

Not Specified Coining&

quartering

Combined

manual &

screening


NSR (Ohlsson,

1998)

Waste

composition

studies. Methods

and trends

Number of

households

Geographic,

demographic,

collection

variables,

single/multi-

family

Not specified Manual

RVF (2005a) NSR solid waste

characterization

method

Mass Single/multi-

family,

community

Modified

Coining&

quartering

Manual

RVF (2005b) Municipal solid

waste

composition

analysis manual

Mass Single/multi-

family,

collection

variables

Cross-section of

elongated, flat pile

Manual

IEA (Scott,

1995)

Work in

harmonising

sampling and

analytical

protocols elated

to MSW

conservation to

energy

Mass Collection

variables

Discusses some

sampling

procedures

Manual

South African

Institution of

Civil

Engineering

(Mbande,

2003)

Appropriate

approach in

measuring waste

generation

composition and

density in

developing areas

Number of

households

Socio-

economic

No sampling

method

Manual

SAEFL (2004) A survey of the

composition of

household waste

Mass Community

type, socio-

economic,

geographic,

collection

billing system

and others

Not specified Manual

University of

Dalarna

(Petersen,

2004)

Waste component

analysis as a

planning tool

Percentage

of

population

Single/multi-

family,

collection

variables

From a 20-cell

grid over a

discharged,

flattened load

Manual

The American Society for Testing and Materials (ASTM) furnishes sampling method for

unprocessed MSW. This method considers sampling as vehicle load and the waste is spitted

using coning and quartering method (Dahlen & Lagerkvist, 2007). When the sample drops

from the vehicle it forms a conical shape arrangement, then it is made into a circular, flat

cake shape and then it is divided into 4 quarters and 2 opposite quarters are selected for

sampling and other 2 quarters are discarded (Coning and Quartering, 1997). The selected

sample is then manually categorized into 13 categories according to ASTM (Standart Test


Method for Determination of the Composition of Unprocessed Municipal Solid Waste, 2003).

According to California Integrated Waste Management Board (CIWMB), the vehicle load is

considered as sampling and the waste is sorted into 9 primary categories and many

subcategories. The composition study is combined with the existing data available in the

CIWMB. In 1971, National Institute of Public Health and Environment (RIVM) introduced

MSW composition in the Netherlands. The waste is stratified into 11 household types, 15

primary components and 100 secondary components. The waste is sorted by using

mechanical and manual process by using conveyor belt, magnetic equipment’s and a vibrator

and a separate laboratory for sorting in this sampling method.

The Environmental Agency of England and Wales assess MSW flow by accounting

commercial, civic amenity, littering, bulk and sweep wastes. The factors influenced for

evaluating the overall characterization of waste defined are respected to demographic data,

geographic location and socioeconomic perspective. University of central Florida conducted

the methodology for MSW by considering the vehicle load as sampling and the waste is

sorted into at least 33 categories and composition results may vary due to seasonal change

and dirt particles. Swedish Association of Waste management, a combined project of RVF,

Lulea University of Technology, the Swedish Sustainability Foundation and NSR AB follows

in steps with Pre-Investigation and design analysis as an initial process followed by sample

collection, splitting of samples, sorting into 9 main categories and 22 Subcategories and

finally ends with calculation of data. Mbande from South African Institution of Civil

Engineering defines that only considering vehicle load sampling and data from weighbridge

will not be enough for calculating the waste flow. Inclusion of local authority’s interview,

information regarding demographic details helps in obtaining better results (Dahlen &

Lagerkvist, 2007).

3.3.2 Sampling Errors

Performing accurate MSW sampling operation is really a challenging task. They are 7 types

of sampling errors defined by Pierre Gy’s Theory of sampling for waste sampling, splitting

and sorting, Table 4 (Dahlen & Lagerkvist, 2007). The sampling error is explained for

household waste, though it can be applied for MSW as it also contains waste from household.

Table 4 Sampling errors to be considered for waste composition

Sampling Errors Cause Remedy

Long-range

Heterogeneity

Fluctuation error

Collection of samples from one

place or areas with similar

properties

Collect samples from

different areas and combine it

to one sample

Periodic Heterogeneity

Fluctuation Error

Sampling is carried out and

compared in different seasons

and situations

Samples should be compared

with respective seasons and

situations

Fundamental Error Sampling solid materials like

packing materials, electronic

materials due to its

heterogeneity in shape and size

of the particle

Increase the sample size

and/or reducing the size of

the particle


Grouping and

Segregation Error

Mother sample is improperly

mixed and unevenly dispersed

Mixing the mother sample

properly before it is dispersed

and the collected samples

should cover all the portion

of the mother sample

Increment Delimitation

Error

Materials with large volume is

not distributed properly, it

happens when coning and

quartering method is used for

selecting the sample

Minimise the surface cut by

sampling in flat and

elongated manner

Increment Extraction

Error

Left out fines and contaminants

in the ground while sampling

the waste

Proper use of tools and

resources helps in minimising

the error

Preparation Error Fines, Contaminants, Materials

blown away by air, Particles

sticking to equipment’s,

Misunderstanding,

Carelessness, Wrong labelling

of collection materials

Use trained and experienced

personnel and try to sort the

waste on the sampling day

4. Method

The project was initially started by reviewing state-of-the-art knowledge and research on

solid waste management strategies. The acquired information and discussion with the

researchers initialized a sample idea on how the generated solid waste can be used and

minimized. Based on the information a field study was planned for waste composition studies

in the Gamodubu landfill to estimate the quantity of waste generated annually in Gaborone

and possible strategies for improved waste management, and the study was carried out for 7

days from 2011/05/06 to 2011/05/12 and the readings were recorded.

4.1 Data Collection

As there are several methods for collecting data and information for proceeding with the

report, the suitable and appropriate method chosen for this projects accordingly discussed

between the authors was by gathering the data from the field and conducting interviews with

the personalities familiar with the system which is going to be analysed.

The collection of information and data was carried out in 2 phases. The first phase took place

in Linkoping, Sweden and the second phase in Gaborone, Botswana. In the first phase,

information regarding solid waste management in Botswana and solid waste generation and

collection details in Gaborone was gathered from existing research articles, journals, books

and case studies concerning the waste generation and treatment methods in developed and

developing countries and its composition. Planning of sampling methods for segregating the

waste was also discussed and a rough draft was documented.

A detailed study was conducted in the Gaborone city on waste circulation, a generation and

collection system and its disposal methods. Earlier visit to landfill helped in gathering


information regarding the waste type, carrier services, scavenging process and quantity of

waste deposited in the landfill.

Compared to other cities in Botswana, Gaborone has a high population density, which intern

serves in generating large quantities of waste per day. As it was not possible to perform a

waste composition study for the whole of the waste, sampling method was used for finding

the composition of solid waste categories. As planned in the first phase vehicles were

selected and sampling was done. Finally, the extracted data and information from both the

phases were roughly drafted initially. Based on the obtained data the result of this project was

formulated.

4.2 Solid Waste Composition Study at Gamodubu landfill

The waste composition study is to identify the amount of waste generated in the respective

region or area. In this case the solid waste composition study is used to identify and quantify

the amount of solid waste generated in the region where most people in Botswana live. The

existing information and data in the city council and Gamodubu landfill clearly states, the

waste generated in Gaborone were collected accordingly to the stratums. The stratums have

numerous garbage collection bins and the waste collection vehicles travel to the respective

stratum and collect waste from all the garbage bins and transport it to the landfill. Waste

collection vehicles are allocated to different stratums by both government and private bodies.

Basically the waste in Gaborone is collected and transported to the landfill accordingly to the

categories like household, commercial and industrial and others. As this project deals only

with Gaborone city, the vehicles carrying the waste from Gaborone was only taken into

account.

The waste composition method applied in this project was not similar to the above described

methods, table 3. The basic idea to perform the waste composition study has been extracted

from the methods as guidance for the project. Most of the methods mainly focus only on the

household waste and some of them uses mechanical equipment for sorting and few does not

possess any sampling method. So, based on the available material, human resources,

geographic, climatic condition and time constraint, unique waste composition method was

discussed and assessed and also sampling errors, table 4 are considered in this field study.

4.2.1 Procedure for Analysing the Solid Waste Composition

Initially the waste was categorized into 4 main primary categories (household waste,

commercial waste, industrial waste and other waste). According to Sharma and McBean

(2006) it was enough to sub categorize to 10 secondary categories to attain the stability of the

waste components. One of the secondary categories (plastics) was further divided into 5 sub

categories. According to the stratums, the vehicles were selected for sampling and 1 vehicle

containing more than 500kg of waste was selected as mother sample every day from each

stratum. Likewise 2 mother samples for the 1 main primary category was sorted for

comparison and for acquiring good results with the consideration of human errors and other

factors like wind and rain which has greater influence on waste in the landfill. So total 8

mother samples, 2 samples from 1 main category was sorted and evaluated. After the

selection of vehicle the waste was unloaded and sorted into 10 secondary categories in


separate containers and it was weighted using an electronic weighing scale and readings were

recorded.

4.2.2 Sample size

The number of mother samples and sample size were decided based on the theory of

convergence. According to this theory there is no need to consider more samples if the

composition of the waste stream is coherent with the composition of the previously sorted

sample. So, sample size with 300kgs was taken from each mother sample and then it was

sorted.

4.2.3 Tools and Equipment used for Sorting

Depending on the size of the team and sample, the tools and equipment were used for sorting,

table 5. In this case the sorting was carried with the team size of 5. Out of five, 2 are from the

project Waste Management in Botswana and the rest 2 are from E-waste Management in

Gaborone. All the projects were carried out at the same place and time as joint venture but,

with unique goals and objective.

Table 5 Tools Used for Sorting

Tools and equipment Quantity

Tarpaulin 1

Shovel 3

Container 12

Weigh scale 1

Tent 1

Metal Bench 2

Helper 2

Helmet 5

Carrier 1

Protection clothes 5

Boots 5

Gloves 5

Mouth mask 15

Grabber 2

Cleaning Brush 2

As the wastes were highly contaminated, presence of several micro-organisms and bacteria

may affect the human health. Considering those aspects helmets, boots, gloves, masks were

used for protection from disease and injury while sorting the waste, table 5.

4.2.4 Sorting Procedure

The selected vehicle was directed to the place where sorting is to be done. The sorting place

was separated from the other waste disposal areas, so that samples will not be mixed with the

existing waste and can be selected only from the mother sample of that respective vehicle.

The waste was unloaded from the vehicle to a tarpaulin which is spread on the ground. The

waste was then levelled manually or by levelling machine and then it was partitioned into 3

segments. Sample of 100kgs was selected from each segment, so a total of 300kgs was

collected from one mother sample. The collected samples were poured on the bench for


sorting. The waste was then sorted into 10 secondary categories and collected in separate

containers. The containers were weighed and the observations were noted. The container

which consists of sorts plastic waste was again sub-sorted into 5 Subcategories and it was

weighed and noted (for more detailed information see appendix 9.15).

Under each primary category the waste was subdivided into 10 secondary categories as paper,

wood, textile, food, rubber or leather, plastics, garden waste, metals, glass and electronic

waste. The plastics were further sub categorized into LPDE and LLDPE, HDPE, PET, PVC,

PP, PS and others it has been coded as code 1 for PET, code 2 for HDPE, code 3 for PVC,

code 4 for LPDE and LLPDE, code 5 for PP, code 6 for PS and code 7 for others, figure.9.

The plastics were sorted using these codes in the plastic bin, figure.8.

Figure 8 Plastic Bins Used for Sorting


Figure 9 Diagrammatic Representation of Waste Categories

4.3 Assessing the Annual Generation Rate

The annual generation rate in Gaborone was approximately assessed based on the output

results obtained from the waste composition study in the landfill. The defined formula was

used to determine the total annual waste generation from the total waste generated per day in

Gaborone. The quantity of waste generated per day in Gaborone obtains from the data and

information available with the landfill operators and city council. For more details and

formula see appendix 9.14.

4.4 Criteria for the Improvement of Better Waste Management System

The improvement for the better waste management system can be defined in short term and

long term scale. The short term improvements such as waste minimisation and prevention,

waste separation at source, improved collection system, transfer centres, knowledge on waste

management to the public, legislation and policies mainly rely on the existing infrastructure,

collection system and waste recovery companies existing in Gaborone city (for more details

see (Shashidhar Suresh, 2011) and (Mesfin Taye, 2011)). Based on the state-of-the-art

knowledge, long term improvements such as construction of recycling plants, production of

bio gas and electricity can be obtained by stabilising the short term improvements. Potential

for resource recovery can be initialized in the long term improvements.


5. Results

5.1 Annual generation of solid waste in Gaborone

The annual amount of solid waste that is transported from Gaborone to the Gamodubu

landfill is close to 50,000 tonnes, Figure 10. As described earlier in the method chapter, this

estimate is based on scaling up the received amounts of waste at the landfill during the six-

day field study to a yearly basis.

Figure 10 Annual generation of solid waste (in tonnes) for different stratums of Gaborone. The presented

amounts only account for the waste delivered to the Gamodubu landfill.

Paper, garden and wood waste, textile, food, metals, glass, electronic waste, plastics and

fines are the waste categories taken into account for the 4 stratums, i.e. housing, commercial,

industrial and others. From this analysis, it is clear that more than half of the received waste

at the landfill originates from households. Waste from the commercial sector accounts for

approximately 30% of the generated waste while the remains are mainly a waste of others

(e.g. Defence waste, Institutional waste). Industrial waste constitutes a minor part of the

waste generated in Gaborone with only 1,600 tonnes per year. For more details on the amount

of waste generated for different stratums see appendix 9.1.

5.2 Annual composition of solid waste from different stratums

The composition of different solid waste categories were analysed according to different

stratums. Each waste category is displayed in terms of weight %, figure 11.


Figure 11 Composition (in weight- %) of the annually generated waste for 4 different stratums in Gaborone

The household stratum produces large quantity of waste from paper (22%), garden and wood

waste (22%) and food waste (25%), as the cooking activities was more on housing, the

quantity of food waste generated is quite higher than the other waste categories. Likewise

commercial sector generates 34% of paper waste, 27% of food waste and 20% of plastics.

Here, the commercial sector such as shopping mall, restaurants use large quantity of paper

products for several activities such as wrapping, advertisement, food holders and more, which

increased the generation of paper compared to other waste. In an industrial sector paper

(45%) constitutes the major part compared to other waste because of documentation, food

activities, etc. The generation of food waste (35%) is quite large in others (defence,

institutional) when compared to other waste categories. On the whole, when all the stratums

are compared, it is clear that the generation of organic waste (paper, food, garden) is high

related to other waste categories.

5.3 Average composition of the solid waste received at the Gamodubu landfill

The average composition of the total analysed amount of waste during the field study at

Gamodubu (i.e. 2400kgs) is shown in Table 6. Organic waste (paper, food, garden and wood)

constitutes more than 50% of the total waste generated in Gaborone. Paper is the largest

waste category, representing approximately 30% of the total generated amount of waste

followed by food with 25% and garden and wood waste with 10%, Figure 12. The remaining

waste categories are not influenced more and have the lowest percentage of flow. The

generation of e-waste is very low as it is often reused by several commodities like schools

and other institutions and services. In the case of metals, virtually this entire waste category

22% 22%

4%

25%

4% 7%

1%

13%

2%

Household (%)

34%

2% 1%

27%

6% 7% 1%

20%

2%

Commercial (%)

45%

3% 3% 16%

7% 6% 1%

13% 6%

Industrial (%)

20% 14%

2%

35%

5% 4% 0%

14% 6%

Others (%)


consists of aluminum cans. The use of metal and plastic packaging for food and beverages are

more common in Gaborone than using glass packaging, so the amount of waste plastic

generated is quite high while the amount of discarded metals is more or less equal to

discarded glass bottles. Fines consist of sand and other particles which cannot be processed

further.

Table 6 Amount of different waste categories in total sample size analysed at the Gamodubu landfill (i.e. 2,400

kg)

Waste Categories Amount of different

waste categories in total

sample size

Paper 719.5

Garden & Wood waste 248.2

Textile 69.45

Food 609.8

Metals 135.25

Glass 131.85

Electronic waste 14.78

Plastics 350.8

Fines & Others 111.5

Total 2391

Figure 12 Average composition (in weight- %) of the total sample size analysed at the Gamodubu landfill

5.4 Total Annual Flow of Different Waste Categories and its Quality

The total annual flow of different waste categories into the Gamodubu landfill is estimated

based on the average composition of waste from different stratums and average amount of

total waste received to the landfill. The annual flow of waste categories from Gaborone to the

landfill is estimated and displayed, Figure 13. Paper and food are the major contributors in

Paper

30%

Garden & Wood

waste

10%

Textile

3%

Food

25%

Metals

6%

Glass

5%

Electronic waste

1% Plastics

15%

Fines & Others

5%

Annual Generation of waste categories in Gaborone


the waste flow with around 15000 and 13000 tonnes per year whereas textile and e-waste has

minimize waste generation and flow to the landfill. This resembles, the waste generated in the

Gaborone city is mainly of organic and decomposable waste and the rest of the waste

categories were inorganic.

From the visual inspection, it is found that the quality of waste is not worthy. The waste that

has been collected and transported to the landfill is not the waste that is generated recently in

the Gaborone city. Apart from that, the waste is mixed up from the source itself and discarded

to the nearby garbage collection centre. Therefore it is very difficult to separate the waste into

different waste categories. For example, the paper waste mixes up with the food and losses its

quality which cannot be used for paper recycling. Formation of worms and other insects are

visualized during the sorting process. These factors degrade the quality of the material or

substance and decrease the efficiency of the product.

Figure 13 Total Annual Flow of Different Waste categories to Landfill

5.4.1 Total Annual flow of different plastic waste categories

In total, 15% of the generated waste in Gaborone is plastics. Almost 50% of this plastic waste

constitutes Low Density Polyethylene (LDPE) & Linear Low Density Polyethylene

(LLDPE), Figure 14. Plastic bags are the main contributors of LLPE & LLDPE. So it

resembles the use of plastic bags and covers for shopping and other purposes are high when

compared to the use of other plastic categories. Polyethylene Terephthalate (PET) bottles

make up 10% of the plastic waste which is comparatively less because of the influence of

metal cans as it is used more widely for liquid and food products.


Figure 14 Composition (in weight- %) of the annually generated plastic waste in Gaborone

6. Discussion

The results show that 57% of the generated solid waste in Gaborone originates from

households, followed by 29% of commercial waste, 11% of others and 3% of industrial waste

(for further details, see appendix 9.18). A significant share of the solid waste is organic waste

(Paper 30%, Food 25%, Garden and Wood waste 10%) and only 35% is inorganic (Plastics

15%, Metals 6%, Glass 5%, Fines 5%, Textile 3%, Electronic waste 1%).

A study of municipal solid waste in the Balkan region shows that the organic share of the

waste in Bulgaria and Romania is 58.3% and 59.2%, respectively (Slavko Dvorsak, 2009-

2010). In fact, there are several other studies demonstrating that the amount of organic waste

often comprises more than 50 % of the total generated solid waste in developing countries (E.

Metin, 2003) (Mohee, 2001) (Issam A. Al-Khatib, 2010).

6.1 Strategies for Improved Waste Management in Gaborone

In Table 7( 8 )

, the environmental potential of implementing a more sophisticated waste

management system in Gaborone is presented. The quantity of waste generated annually in

Gaborone has the potential to generate electricity from organic and combustible waste.

Inorganic materials have the potential in raw materials conservation and reduced GHG

emission. However, in order to realize the overall potential of resource recovery of waste in

Gaborone, large investments will be needed for developing waste collection sites,

transportation systems and treatment and recycling plants – investments that probably only

will be possible in a long-term perspective.

8 For reference see (3.2.3, 3.2.5, 3.2.4.2)

PET 10% HDPE

19%

PVC 5%

LDPE & LLDPE

46%

PP, PS & others 20%

Percentage of different plastic waste categories

generated annually


Table 7 Potential for resource recovery of the generated solid waste in Gaborone

Waste Category Quantity of

waste generated

annually (tonnes)

Potential

treatment

method

Environmental potential

Paper

15000

Material

recycling

Saves 45 – 60 GWh(9)

of

electricity

Saves 34*103 cubic metres of

landfill space

Saves energy equivalent to

365 terrajoule of gasoline

255*103 trees can be saved

Combustible waste

(paper, textile,

plastic, garden and

wood)

28500

Incineration

with energy

recovery

15 GWh of electricity can be

generated

Organic waste (food,

garden and wood)

18000 Anaerobic

digestion

18*106 - 36*10

6 cubic metres

of biogas can be produced

Metals (Aluminium)

3000

Material

recycling

Saves 18 kilotonnes of

bauxite, 12 kilotonnes of

chemical and 42 GWh of

electricity

Glass

3000

Material

recycling

36*102 tonnes of raw material

are conserved

945 tonnes of CO2 emission

are reduced by the facility

Plastic 7000 Material

recycling

Saves 396*102 cubic metres of

landfill space

So, in this thesis, more emphasis is on short-term improvement strategies, relying on what

has already existed in the region when it comes to waste collectors, recovery and treatment

plants.

6.1.1 A need for introducing source separation systems

Source sorting is the basic and most important factor for improved waste management since

mixed waste offers largely limited possibilities for resource recovery. Many of the European

countries like Sweden, practise source sorting. The present solid waste generated in Gaborone

is however not separated but virtually always collected as a mixed waste. Once mixed, it is

difficult for recovery companies and the city council to separate the waste into different

usable material categories for further treatment or recycling. Accordingly, there is a need for

establishing recycling stations at strategic locations in Gaborone, to which the citizens can

bring their waste for sorting. If possible, separate bins or containers should be provided for

paper, food, plastic, metals, glass, e-waste, textile and garden waste. By just introducing a

separate collection of paper and food waste, the amount of waste being landfilled could

potentially be reduced by 50% because the quantity of paper and food waste generated in

9 Gigawatt hour


Gaborone is more than 50% from the analysis, see Figure 13. For paper waste, there are

already existing collectors in the region and the collected food waste could be treated by

composting in order to produce soil fertilizers. Composting is a relatively simple and

inexpensive treatment method, which might be able to fit into the present social-technical

regime of Gaborone.

6.1.2 Improved collection system

The sorted waste in the recycling stations is then collected by waste collection vehicles. Due

to the long transportation distances to the Gamodubu landfill, a transfer station should be

introduced in the outskirts of the city. Here, the collected waste at recycling stations could be

temporarily stored and later the different waste categories can be distributed to their desired

location. Existing paper, glass, plastic recovery companies could collect their material either

directly from the recycling stations or from the transfer station. The residual mixed waste can

be disposed in the Gamodubu landfill, Figure 15. In case, metals or other valuable materials

still are occurring in the waste, additional recovery will take place at the landfill in terms of

scavengers collecting materials for the exiting waste collectors in the region.

The generated waste near the stratums should be collected periodically, so that the waste will

not degrade much and does not produce the odour smell. Apart from recycling stations,

plastic bottles and metal cans can also be collected by using the “Drop In and Get Paid”

method. Many of the European countries are following this kind of strategy for collecting

plastic and metal cans. In this method, collection machines are placed in shopping malls and

residential areas, and then the individual is given revenue dependent on the number and type

of bottles/cans. These types of improved collection systems will largely minimize the

quantity of waste needing transportation to the landfill and will also provide significantly

more raw material for the existing waste recovery companies in the region.


Figure 15 Schematic illustration of an improved waste management system in Gaborone

Enhanced landfill mining (ELFM) is an approach that is practised in some of the European

countries at present. In principle, this strategy means that collected valuable materials such as

metals and e-waste that are intentionally stored in separate cells and covered areas of the


landfill in order to facilitate future material valorisation, i.e. when sufficient technologies and

recycling plants have been developed. (Hogland, Hogland, & Marques). Resource scarcity,

material hibernation can be avoided by initialising ELFM. For more details see appendix

9.18.

6.1.3 Social Considerations

Government should create awareness among the public on waste management and its

applications and impacts. Awareness and knowledge sharing programs should be conducted

by the government and non-governmental organisation to increase Batswana skills and

thinking ability to waste. On the policy level, legislation and economic instruments could also

be implemented in order to create stronger incentives for providing alternatives to landfilling.

Such an approach has been widely used in the European region in terms of successively

implemented bans and taxes on landfilling of waste. However, one critical condition for

facilitating realization of the suggested measures is a stronger collaboration between the

government and existing waste recovery companies in the region. Such collaborative

approaches, e.g. public-private partnerships, enables the sharing of costs and benefits related

to developing a more sophisticated waste management system in Gaborone. For instance,

separate collection of paper waste will largely limit the transportation costs for the

government while existing paper collectors will receive significantly more “raw material”.

More detailed studies are however needed in order to illuminate the potential of such

collaborative approaches and if they really have the capacity of creating mutual benefits for

the actors involved in the waste management in the region.


7. Conclusion

The findings in this project present the current solid waste generation, collection and disposal

methods in Gaborone, Botswana. The strategy for waste management in Gaborone was

mainly driven by the private and government sectors. From the analysis it’s clear that large

quantity of solid waste generated in Gaborone is due to lack of environmental awareness,

improper waste management practice, public-private partnerships, collaborative approaches

and less social-economic considerations. The collection system for solid waste is

comparatively effective in Gaborone but it should be further improved more economical and

periodically. Transportation and disposal of waste are the major conflict in the city. All solid

waste which is generated and collected is disposed directly into the landfill without any waste

treatment methods. This affects the life of the landfill as well as the environment by polluting

air, water and soil and also leads to depletion of resources. The waste composition study in

Gaborone results the annual waste generated in the Gaborone and its composition shows the

percentage of waste categories of different stratums. The composition study shows, the

quantity of organic waste present in the total waste is high when compared to other waste

categories generated in Gaborone. A need for introducing the source separation system,

introducing improved collection system, application of waste treatment techniques and

creating social consideration among the people helps to promote the possibility for long term

improvement and also to find out the potential for improved waste management system,

which serves in improvising fastest growing and developing country into a developed

country. These improvements will lead to a better waste management system in the future

and also creates employment opportunities and awareness among the people on waste

management system. Supportive of governmental and non-governmental organisations,

policies and measures largely influence in building up the improvements for a sustainable

waste management system.


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9. Appendix

9.1 Data Collection from Each Stratum

9.1.1 Household (Vehicle 1)

Stratum Household waste Vehicle Reg. No. B390ARV

Client Gaborone City Council Gross weight 28300 kg

Department Gaborone City Council Vehicle weight 15780 kg

Waste type Domestic waste Waste weight 12520 kg

Waste type code A *Total fee P500.85

Rate 0.04 per kg

Waste Categories Weight (kg)

Paper 79.60


Textile 12.20

Food 84.25

Metals 18.55

Glass 12.45


Plastics 47.30

Fines & Others 1.70

Plastic Categories Weight (kg)

PET (code – 1) 6.05

HDPE (code – 2) 12.80

PVC (code – 3) 1.80

LDPE & LLDPE (code – 4) 14.55

PP (code – 5), PS (code – 6) & others (code – 7) 7.60

9.1.2 Household (vehicle 2)

Stratum Household waste Vehicle Reg. No. B115ARS

Client Gaborone City Council Gross weight 19580 kg

Department Gaborone City Council Vehicle weight 12840 kg



Rate 0.04 per kg



Paper 55.05


Textile 15.20

Food 59.30

Metals 10.00

Glass 25.65


Plastics 30.30



PET (code – 1) 3.15

HDPE (code – 2) 5.50

PVC (code – 3) 0.20



9.1.3 Commercial (Vehicle 1)

Stratum Commercial waste Vehicle Reg. No. B875AIB

Client Skip Hire Gross weight 13020 kg

Department Skip Hire Vehicle weight 10000 kg



Rate 0.04 per kg


Paper 92.40


Textile 1.45

Food 92.35

Metals 14.25

Glass 34.85


Plastics 50.50



PET (code – 1) 4.05



PVC (code – 3) 4.00



9.1.4 Commercial (Vehicle 2)

Stratum Commercial waste Vehicle Reg. No. B875AIB

Client Skip Hire Gross weight 13940 kg

Department Skip Hire Vehicle weight 9780 kg



Rate 0.04 per kg


Paper 113.50


Textile 4.00

Food 79.40

Metals 16.25

Glass 10.10


Plastics 61.75

Fines & Others 1.20


PET (code – 1) 4.10


PVC (code – 3) 2.95



9.1.5 Industrial (Vehicle 1)

Stratum Industrial waste Vehicle Reg. No. B721AMJ

Client Diamond Trading Company Gross weight 4220 kg

Department Diamond Trading Company Vehicle weight 3680 kg



Rate 0.04 per kg



Paper 134.30


Textile 0.75

Food 85.55

Metals 6.45

Glass 5.50


Plastics 36.40



PET (code – 1) 1.55


PVC (code – 3) 0.05



9.1.6 Industrial (Vehicle 2)

Stratum Industrial waste Vehicle Reg. No. B155AJZ

Client Cleaning Wizards Gross weight 9080 kg

Department Cleaning Wizards Vehicle weight 8800 kg



Rate 0.04 per kg


Paper 121.30


Textile 20.70

Food 8.70

Metals 40.35

Glass 17.75


Plastics 38.60



PET (code – 1) 1.90

HDPE (code – 2) 13.50


PVC (code – 3) 4.50



9.1.7 Others (Vehicle 1)

Stratum Other waste Vehicle Reg. No. BDF7018

Client SSKB BDF Gross weight 18540 kg

Department SSKB BDF Vehicle weight 17200 kg



Rate 0.04 per kg


Paper 47.05


Textile 10.50

Food 96.10

Metals 7.00

Glass 20.95


Plastics 28.15



PET (code – 1) 3.60


PVC (code – 3) 0.65



9.1.8 Others (Vehicle 2)

Stratum Other waste Vehicle Reg. No. B249AMM

Client Petrib Marketing Services Gross weight 3340 kg

Department Petrib Marketing Services Vehicle weight 2120 kg



Rate 0.04 per kg



Paper 76.30


Textile 4.65

Food 104.15

Metals 22.40

Glass 4.60


Plastics 57.80



PET (code – 1) 6.50


PVC (code – 3) 3.15



9.2 Total Amount of Solid Waste generated in the Gamodubu landfill on 2011/05/07


Waste Quantity

(kg)

*Amount

(Pula)

Domestic waste A 194440 6088.58

Garden waste B 6620 116.41

Medical waste C 980 17401.74

Tires D 2760 0

Soil material F 940 0

Recyclable tires Q 200 0

9.3 Total Amount of Solid Waste Generated in Landfill on 2011/05/07 based on Stratum

Stratum

Waste Quantity

(kg)

Household waste 101360

Commercial waste 32580

Industrial waste 2140

others 4580




Waste Quantity

(kg)

*Amount

(Pula)




Tires D 860 0


Wood waste P 160 0


9.5 Total Amount of Solid Waste Generated in Landfill on 2011/05/08 based on

Stratum

Stratum

Waste Quantity

(kg)




others 12120



Waste Quantity

(kg)

*Amount

(Pula)




Tires D 1500 0


Condemned food stuffs J 3200 64.01

Recyclable papers K 3440 0


Recyclable metals R 2640 0


Stratum

Waste Quantity

(kg)




others 14860




Waste Quantity

(kg)

*Amount

(Pula)




Tires D 8260 413.04



Elec. And Electrical waste N 60 2.4



Stratum

Waste Quantity

(kg)




others 17020



Waste Quantity

(kg)

*Amount

(Pula)




Tires D 8920 446.04

Scrap metal E 720 0


Condemned food stuffs J 4060 81.21




Food animal waste W 500 500.05


9.11 Total Amount of Solid Waste Generated in Landfill on 2011/05/11 based on

Stratum

Stratum

Waste Quantity

(kg)




others 22720

9.12 Overall Waste generation in landfill from (2011/05/06 – 2011/05/11)

Stratum

Overall amount of waste generated in

the landfill (kg)

Household 463780

Commercial 242180

Industrial 25660

Others 87640

9.13 Total Amount of Waste composition of plastic from the samples (2400kgs)

Plastic Categories Overall Weight (kg)

PET (code – 1) 30.9


PVC (code – 3) 17.3



9.14 Calculation for assessing the annual generation rate of waste

(Total annual waste generation in Gaborone = Total waste generated per day * 365 days)

But, for calculating the total annual waste generation for each stratum and category the

following formula is used.

Total waste generation per day = ((Total waste generated from 2400( 10 )

kg/2400kg)*

Total waste generated during study period in

Gaborone))/6

10 2400kg= 300(sample size)*8 (No.of Vehicles)


For example,

Total waste generation of paper per day = (Total paper waste generated from

2400kg/2400kg)* Total waste

generated during study period in

Gaborone))/6

(Total annual paper waste generation in Gaborone = Total waste generation of paper per

day * 365 days)

a) For paper

Total waste generation of paper per day = ((Total paper waste generated from


generated per day in Gaborone))/6

Total waste generation of paper per day = (719.5/2400kg)* 819260))/6

= 40934kg

Total annual waste generation of paper = 40934*365 => 14941 ~= 15000 tonnes

b) For Garden & Wood waste

Total waste generation of garden & wood per day = ((Total paper waste generated from



Total waste generation of garden & wood per day = (248.2/2400kg)* 819260))/6

= 14120kg

Total annual waste generation of garden & wood = 14120*365 => 5154 ~= 5000 tonnes

c) For Textile

Total waste generation of textile per day = ((Total paper waste generated from



Total waste generation of textile per day = (69.45/2400kg)* 819260))/6

= 3951kg

Total annual waste generation of textile = 3951*365 =>1442 ~= 1500 tonnes

d) For Food

Total waste generation of food per day = ((Total paper waste generated from




Total waste generation of food per day = (609.8/2400kg)* 819260))/6

= 34693kg

Total annual waste generation of food = 34693*365 =>12663 ~= 13000 tonnes

e) For plastics

Total waste generation of plastics per day = ((Total paper waste generated from



Total waste generation of plastics per day = (350.8/2400kg)* 819260))/6

= 19958kg

Total annual waste generation of plastics = 19958*365 =>7284 ~= 7000 tonnes

f) For metals

Total waste generation of metals per day = ((Total paper waste generated from



Total waste generation of metals per day = (135.25/2400kg)* 819260))/6

= 7694kg

Total annual waste generation of metals = 7694*365 =>2808 ~= 3000 tonnes

g) For Glass

Total waste generation of glass per day = ((Total paper waste generated from



Total waste generation of glass per day = (131.85/2400kg)* 819260))/6

= 7501kg

Total annual waste generation of glass = 7501*365 =>2737 ~= 3000 tonnes

h) For E-waste

Total waste generation of plastics per day = ((Total paper waste generated from



Total waste generation of plastics per day = (14.78/2400kg)* 819260))/6

= 840kg

Total annual waste generation of plastics = 840*365 =>306 ~= 300 tonnes


i) For Fines & Others

Total waste generation of fines & others per day = ((Total paper waste generated from



Total waste generation of fines & others per day = (111.5/2400kg)* 819260))/6

= 6343kg

Total annual waste generation of fines & others = 6343*365 =>2315 ~= 2000 tonnes


9.15 Pictures of Sorting Procedure


9.16 Pictures Taken in the Landfill

Materials used for Sorting Place used for Sorting

Waste unloaded form Vehicle Helper sorting the Waste


Container used to collect Sorted Waste Weigh scale

Researchers working in landfill weigh scale for Weighing Vehicles

Sorted waste is weighed and Recorded Food waste mixed with paper


Solid waste spread in Landfill Disposing solid waste in landfill

Collect-A-Can Company recovers metal can for recycling

Simple Recycle Company recovering plastic for recycling


Plastics are processed to raw material in simple recycle plant

“Skip Hire” Carrier used to collect waste from commercial and industrial stratum

9.17 Pictures of Plastics Sorted into Sub categories


9.18 MSW generation based on regions and countries


Source (I. Korner, 2003-2006)


9.18 Enhanced landfill mining flow diagram

ELFM process flow diagram

Source (Tielemans & Laevers)

solid waste generation & composition in gaborone, …488964/fulltext01.pdfcomposition in...

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